Experimental Methods for Rehabilitation of Distressed Steel Structures

Bridges are one of the important structures constructed to bridge the depressions along the alignment of roads, irrigation canals, water lines etc. In the year 2008, a project (worth Rs 26 crore) of laying water pipeline from Rangil water treatment plant to Shalteng, Srinagar was won by Pratibha Industries Ltd Mumbai. Along its alignment a truss girder pipe rack was constructed to bridge this water supply pipe (diameter 700mm) across the Jehlum river. The pipe rack constituted four spans of 37.5m each. The bridge trusses were fabricated in Jalandhar (Punjab) and each span transported to the site in four parts. Due to fabrication error i.e. the length of each span of the bridge was fabricated 37m instead of 37.5m. To make up this length deficiency in each span, inadequate measures were taken at site by engaging inexperienced fabricator. After just few months of commissioning the bridge, the monitoring team observed distress in the structure noticeable in the form of a tilt. Unfortunately, a newly constructed pipe rack was severely in distress making it vulnerable to collapse under earthquake loading of seismic Zone V.